JP2000111763A - Light transmission system and signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for efficiently converging signal lights to a signal light receiving part, and for realizing miniaturization even in a structure corresponding to integration into multi-bits by directing incident signal lights to a light diffusing means, and collimating the signal lights diffused and emitted from the other edge. SOLUTION: When signal lights are emitted from a light emitting element 61 of one circuit board 6, the signal lights are made incident on a linear Fresnel lens 3, and the optical paths are converted by the linear Fresnel lens 3 so that the inputted signal lights can be directed to a light diffusing body 2. Then, when signal lights 611 reach the light diffusing body 2, the signal lights 611 are diffused and propagated to a linear Fresnel lens 4. The signal lights diffused by the light diffusing body 2 and made incident on the linear Fresnel lens 4 are collimated. The large part of the signal lights collimated by the part opposed to each light collecting sheet 5 of the linear Fresnel lens 4 among the signal lights collimated by the linear Fresnel lens 4 are made incident on each light collecting sheet 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical transmission system for transmitting an optical signal and a signal processing apparatus for performing signal processing including transmission and reception of data using the optical transmission system.

[0002]

2. Description of the Related Art With the development of very large scale integrated circuits (VLSI), circuit functions of circuit boards (daughter boards) used in data processing systems have been greatly increased. As the number of signal connections to each circuit board increases as circuit functions increase, the data bus board (motherboard) that connects each circuit board (doder board) with a bus structure requires a large number of connectors and connection lines. Has been adopted. Although parallelization has been promoted by increasing the number of connection lines and miniaturization, the operation speed of the parallel bus has been improved.However, the processing speed of the system has been reduced due to the signal delay caused by the capacitance between connection lines and the connection line resistance. May be limited by the operating speed of the device. In addition, electromagnetic noise (EMI: Elec) caused by increasing the density of parallel bus connection wiring
(tromagnetic Interference)
The problem described above is also a great constraint on improving the processing speed of the system.

In order to solve such a problem and improve the operation speed of the parallel bus, use of an in-system optical connection technique called optical interconnection has been studied. The outline of the optical interconnection technology is described in “Sadaji Uchida, Academic Lecture Meeting on Circuit Packaging, 15C01, pp. 146-64”. 201
-202 ”and“ Hisami Tomomi, et al., “Current Situation and Trend of Optical Interconnection Technology”, IEEE Tokyo Sect.
ion Denshi Tokyo No. 33 p
p. 81-86, 1994], various modes are proposed depending on the configuration of the system.

[0004] Among various types of optical interconnection techniques proposed in the past, Japanese Patent Application Laid-Open No. 2-41042 discloses an optical data transmission system using a high-speed, high-sensitivity light emitting / receiving device applied to a data bus. An example is disclosed in which light emitting / receiving devices are arranged on both front and back surfaces of each circuit board, and light emitting / receiving devices on adjacent circuit boards incorporated in the system frame are spatially optically coupled. A serial optical data bus for loop transmission between circuit boards has been proposed. In this method, signal light transmitted from one circuit board is transmitted to an adjacent circuit board by light / light.
Each of the circuit boards is sequentially arranged in series so that the electrical conversion is performed, the electrical / optical conversion is performed once again on the circuit board, and the signal light is transmitted to the next adjacent circuit board. Is transmitted between all circuit boards incorporated in the system frame while repeating electrical / optical conversion. For this reason, the signal transmission speed depends on the optical / electrical conversion / electrical / optical conversion speed of the light receiving / light emitting device arranged on each circuit board and is also restricted by the speed. In addition, since data transmission between each circuit board uses optical coupling via a free space by a light receiving / light emitting device arranged on each circuit board, it is arranged on both front and back surfaces of an adjacent circuit board. It is necessary that the light emitting / receiving devices are optically aligned and all the circuit boards are optically coupled. Furthermore, since the optical data transmission lines are connected via free space, interference between adjacent optical data transmission lines (crosstalk) occurs.
Occurs and data transmission failure is expected. In addition, it is expected that data transmission failure occurs due to scattering of signal light due to an environment in the system frame, for example, dust or the like. Furthermore, since the circuit boards are arranged in series, if any one of the boards is removed, the connection is interrupted there, and an extra circuit board is required to compensate for the disconnection. That is, there is a problem that the circuit board cannot be freely inserted and removed, and the number of circuit boards is fixed.

A data transmission technique between circuit boards using a two-dimensional array device is disclosed in Japanese Patent Laid-Open No. 61-196.
No. 210 discloses this. The technology disclosed herein includes a plate having two parallel surfaces and opposed to a light source, and optically connects between circuit boards via an optical path formed by a diffraction grating and a reflective element arranged on the plate surface. It is a method to combine with. In this method, light emitted from one point can be connected to only one fixed point, and it is not possible to connect all circuit boards comprehensively like an electric bus.
Since an integrated complex optical system including a diffraction grating and a reflective element is required, and alignment is difficult, interference (crosstalk) between adjacent optical data transmission lines occurs due to a displacement of the optical element. Data transmission failure is expected, connection information between circuit boards is determined by the diffraction grating and reflection element arranged on the plate surface, so the circuit board can not be freely inserted and removed, and the expandability is low. There are various problems.

Another technique for transmitting data between circuit boards using a two-dimensional array device is disclosed in Japanese Patent Laid-Open No. 4-1344.
No. 15 discloses this. The technology disclosed herein is based on a lens array in which a plurality of lenses having a negative curvature are formed on the surface of a transparent material having a higher refractive index than air, and a light emitted from a light source. An optical system for making light enter from the side surface of the lens array is used. Also, instead of a plurality of lenses having a negative curvature,
A technique using a region having a low refractive index and a hologram is also disclosed. In this technology, the light incident from the side is distributed to the surface from a plurality of lenses having the above negative curvature, or a region having a low refractive index or a portion formed with a hologram, and the data is emitted using the function of emitting the light. Transmitting. Therefore, it is conceivable that the intensity of the output signal varies due to the positional relationship between the incident position and the output position on the surface where the plurality of lenses or the low refractive index or the hologram is formed. In addition, it is considered that the ratio of light incident from the side surface to escape from the opposite side surface is high, and the efficiency of light used for signal propagation is low. Furthermore, it is necessary to arrange the optical input element of the circuit board in a plurality of lenses having a negative curvature formed on the surface and a region having a low refractive index instead of the lens or a hologram, so that the circuit board is arranged. There are various problems that there is no degree of freedom and the expandability is low.

As means for solving these problems, there is a sheet-shaped optical bus disclosed in Japanese Patent Application Laid-Open No. 10-123350. Since the optical bus diffuses and propagates the signal light that has entered the inside and emits the signal light to the outside, it is possible to transmit the signal light that enters from a certain incident point to a plurality of emission points. Also, this optical bus
Optical coupling with a plurality of circuit boards having light emitting and receiving portions can be easily performed, and precise optical alignment is not required. In addition, the number of circuit boards and the mounting positions of those circuit boards can be freely changed, and a highly expandable and highly flexible system can be constructed. Further, since the optical bus transmits and transmits the signal light not through the free space but inside the optical bus, scattering of light due to dust and the like is prevented, and data transmission failure is prevented. However, since this optical bus diffuses the incident signal light in all directions, most of the light is emitted to portions other than the light receiving portion.
Therefore, the light intensity at the light receiving section becomes very weak, and there is a problem in achieving high speed and low power consumption. In order to solve this problem, as a sheet-shaped optical bus, a signal light incident portion is provided at one end and a signal light emitting portion is provided at the other end on the opposite side. It is conceivable to employ an optical bus provided with a light diffusing unit and provided with an optical transmission layer for diffusing the signal light toward the signal light emitting unit by the light diffusing unit. In this optical bus, the light use efficiency can be improved by controlling the light diffusion distribution of the light diffusion means provided in the signal light incident portion, and the speed is higher than that of the optical bus disclosed in JP-A-10-123350. However, the sheet-type optical bus provided with the light diffusing means at the signal light incident portion has the following problems.

[0008]

When data transmission between a plurality of circuit boards is performed by employing the optical bus having the above-described light diffusing means, the plurality of circuit boards on which the light emitting elements are mounted are mounted on the plurality of circuit boards. The light emitting elements of the plurality of circuit boards are arranged along the edge of the optical bus so as to face the edge on the signal light incident side, and the plurality of circuit boards on which the light receiving elements are mounted are formed by the plurality of circuit boards. The light receiving elements of the circuit board are arranged along the edge of the optical bus so as to face the edge on the signal light emitting portion side. Therefore, the light receiving elements that are adjacent to each other in opposition to the edge of the optical bus on the signal light emitting portion side have at least both the thickness of the circuit board itself and the thickness of the circuit mounted on the circuit board. It is arranged at intervals of minutes.
Therefore, a part of the signal light that is diffused and propagated toward the edge provided with the signal light emitting portion by the light diffusing means is propagated between the light receiving elements adjacent to each other, that is, in a place where there is no light receiving element. However, there is a problem that the use efficiency of the signal light is reduced. In order to solve this problem, it is conceivable to provide a condensing lens having a diameter larger than the diameter of the light receiving surface of the light receiving element between the signal light emitting portion and the light receiving element. When an optical bus corresponding to multi-bits is configured by stacking, it is necessary to dispose each of these optical transmission layers at a position corresponding to each of the condenser lenses. Therefore, if the diameter of each of the condensing lenses is increased in order to increase the utilization efficiency of the signal light, it is necessary to increase the pitch of the optical transmission layer, and the optical bus itself becomes large. . In order to solve this problem, for example, it is conceivable to form the end surface of the optical bus on the signal light emitting portion side on a cylindrical lens surface having a light condensing action in the width direction of the optical transmission layer toward the light receiving element. But,
If light is condensed in the width direction of the light transmission layer, the light will diffuse in the thickness direction of the light transmission layer when the light travels by the focal length, and the light will be efficiently directed to the light receiving element. There is a problem that light cannot be collected.

In view of the above circumstances, the present invention provides an optical transmission system capable of efficiently condensing signal light on a signal light receiving unit and having a reduced size even with a structure corresponding to multi-bits. It is an object of the present invention to provide a signal processing device employing the optical transmission system.

[0010]

A first optical transmission system according to the present invention has the following features. (1) It has a shape that spreads two-dimensionally, and enters signal light from one edge and converts the incident signal light to the other. An optical bus main body that propagates toward the edge of the optical bus and emits the signal light from the other edge, and has an optical diffusion means for diffusing the signal light at a predetermined point in the optical bus main body. A main body, an optical path conversion unit provided on the one edge side for directing the incident signal light to a light diffusion unit arranged at the predetermined point, and the light diffusion unit provided on the other edge side An optical bus provided with a collimating means for collimating the signal light emitted from the other edge diffused by the above (2) provided on the other edge side of the optical bus main body;
The collimator has a shape that spreads in the same direction as the optical bus main body, and the collimator includes a condensing element that condenses a part of the collimated signal light.

The second optical transmission system according to the present invention has the following features. (1) The optical transmission system has a two-dimensionally spread shape, receives signal light from one edge, and directs the incident signal light to the other edge. A plurality of light transmission layers that propagate and emit the signal light from the other edge, and a plurality of light transmission layers having light diffusion means for diffusing the signal light at each predetermined point in each light transmission layer,
An optical bus body in which one edge of each of the plurality of optical transmission layers faces in the same direction and the other edge faces in the same direction and is sequentially stacked; An optical path converting means provided on one edge side of the optical bus body for directing incident signal light to each light diffusing means arranged at a predetermined point of each of the plurality of optical transmission layers; and the other edge side of the optical bus main body. And a collimating means for collimating the signal light diffused by the respective light diffusing means and emitted from the other end of the optical bus main body. (2) The other end side of the optical bus main body A portion of the signal light that is provided corresponding to each of the plurality of light transmission layers and has a shape that spreads in the same direction as the light transmission layer, and is emitted from the corresponding light transmission layer and collimated by the collimating means. Focus Characterized by comprising a plurality of condensing elements arranged in the stacking direction of the light transmission layer.

The signal processing device according to the present invention includes: (1) a base; (2) a signal light emitting body for emitting signal light and a circuit for generating a signal carried by the signal light emitted by the signal light emitting body. A plurality of first circuit boards; (3) a signal light incident body on which the signal light is incident, and a part of the signal light having a shape which spreads two-dimensionally and which is collimated by the collimating means to the signal light incident body. A light-collecting element that emits light,
And a circuit for performing signal processing based on a signal carried by the signal light incident from the signal light incident body.
(4) having a shape that spreads two-dimensionally, receives signal light from one edge, propagates the incident signal light toward the other edge, and transmits the signal light from the other edge. An optical bus main body for emitting light, the optical bus main body having a light diffusing means for diffusing the signal light at a predetermined point in the optical bus main body, and the incident signal light provided on the one edge side. An optical path changing means for directing the light to the light diffusing means arranged at the predetermined point,
An optical bus provided on the other end side and provided with a collimating unit for collimating the signal light diffused by the light diffusing unit and emitted from the other end; (5) each of the plurality of first circuit boards Is fixed on the base in a state where each of the signal light emitting bodies mounted on each of the plurality of first circuit boards is optically coupled to one edge of the optical bus, and the plurality of The two circuit boards are arranged such that the light-collecting elements mounted on the second circuit boards respectively extend in the same direction as the optical bus extends, and are optically coupled to the other end of the optical bus. A plurality of base fixing portions fixed on the base in the state are provided.

[0013]

FIG. 1 is a top view showing a signal processing apparatus according to a second embodiment of the present invention provided with a first optical transmission system according to the first embodiment of the present invention, and FIG. FIG. 2 is a diagram of the signal processing device viewed from the AA direction. In FIG. 2, the optical bus 20 included in the optical transmission system is A
A cross-sectional view as viewed from the -A direction is shown.

As shown in FIG. 1, the signal processing apparatus 100 includes an optical transmission system 50 including an optical bus 20 and four light-collecting sheets 5 having a two-dimensionally spread shape. The optical bus 20 includes an optical transmission layer 1 having a two-dimensionally spread shape and transmitting signal light. The light transmission layer 1 forms the main body of the optical bus 20. Here, as the light transmission layer 1, PMMA (polymethyl methacrylate) having a high light transmittance and molded to a thickness of 0.5 mm is used. I have. At the center of the light transmission layer 1, a columnar light diffuser 2 for diffusing signal light is provided.
A linear Fresnel lens 3 (an example of an optical path changing means according to the present invention) is adhered to one end face of the optical transmission layer 1, and a linear Fresnel lens 4 (an example of a collimating means according to the present invention) is adhered to the other end face. ) Is glued. These linear Fresnel lenses 3 and 4 have the same shape as each other,
Each has a focus on the light diffuser 2. Here, the same PMMA as the material of the light transmission layer 1 is used as the material of the linear Fresnel lenses 3 and 4. The operation of the linear Fresnel lenses 3 and 4 will be described later.

In order to manufacture the light transmission layer 1 and the linear Fresnel lenses 3 and 4 described above, for example, a mold for each of the light transmission layer and the linear Fresnel lens into which PMMA is poured is prepared. The PMMA may be heated to a temperature at which it can be melted, and the sufficiently heated and molten PMMA is poured into each mold, cooled slowly over time, and then removed from each mold.

The signal processing device 100 includes four circuit boards 6 arranged along the linear Fresnel lens 3.
And four circuit boards 7 arranged along the other linear Fresnel lens 4. Circuit boards 6, 7
Among them, on the circuit board 6, a light emitting element 61 for emitting signal light and a circuit (not shown) for generating a signal to be carried by the signal light emitted from the light emitting element 61 are mounted. The light emitting element 61 mounted on each circuit board 6 is disposed at a position facing the linear Fresnel lens 3.
A light receiving element 71 for receiving signal light is provided on the circuit board 7.
And a light-collecting sheet 5 constituting the optical transmission system 50, and a circuit (not shown) for performing signal processing based on a signal carried by the signal light received by the light receiving element 71. A notch is provided in a portion of each circuit board 7 facing the linear Fresnel lens 4, and the notch is
As shown in the figure, the light-collecting sheet 5 is inserted. The light-collecting sheet 5 is formed to have the same thickness as the light transmission layer 1. The light-collecting sheet 5 is arranged at a position facing the linear Fresnel lens 4 so as to spread in the same direction as the direction in which the light transmission layer 1 spreads. The end surface of the light-collecting sheet 5 facing the linear Fresnel lens 4 is a cylindrical lens surface 5a, and the cylindrical lens surface 5a has a focal point on the opposite end surface 5b. The light receiving element 71 is mounted such that the light receiving surface thereof comes into contact with the end face 5 b of the light-collecting sheet 5.

Hereinafter, the manner in which the light emitting element emits signal light and the signal light is received by the light receiving element will be described with reference to FIGS. 3 and 4 and FIGS. 1 and 2 as necessary.

FIG. 3 is a diagram showing the right half (on the side of the linear Fresnel lens 4) of the optical bus shown in FIGS. 1 and 2, and a circuit board 7 arranged to face the linear Fresnel lens 4.
FIG. 4 is an enlarged side view of a portion where the linear Fresnel lens 4, the light collecting sheet 5, and the light receiving element 71 are arranged.

Signal light is emitted from the light emitting element 61 of one of the four circuit boards 6 (see FIG. 1) (here, the circuit board disposed at the innermost side in FIG. 1). When emitted, the signal light enters the linear Fresnel lens 3. The linear Fresnel lens 3 converts the optical path so that the signal light incident on the linear Fresnel lens 3 goes to the light diffuser 2. More specifically, the linear Fresnel lens 3 does not change the optical path in the thickness direction of the light transmission layer 1, but has a focus on the light diffuser 2. Is converted in the width direction of the light transmission layer 1 (longitudinal direction of the linear Fresnel lens 3) toward the light diffuser 2.
Therefore, the signal light incident on the linear Fresnel lens 3 is
The signal light 611 is converted into an optical path toward the light diffuser 2 in the width direction of the light transmission layer 1 and propagates in the light transmission layer 1.

The light diffuser 2 included in the light transmission layer 1
Is a light transmission type light diffusion that diffuses the signal light incident on the linear Fresnel lens 3 and reaching the light diffuser 2 toward the opposite linear Fresnel lens 4 over the entire length of the linear Fresnel lens 4. Body. Therefore, the signal light 61
When 1 reaches the light diffuser 2, the signal light 611 propagates toward the linear Fresnel lens 4 while diffusing.
The light diffuser 2 has a columnar shape, but may have a spherical shape, a rectangular parallelepiped shape, or an elliptical shape, for example. Of the signal light diffused by the light diffuser 2, the signal light propagating toward the linear Fresnel lens 4 while being totally reflected on the front and back surfaces of the optical transmission layer 1, and the signal light propagating directly toward the linear Fresnel lens 4 Light reaches the linear Fresnel lens 4. In FIG. 3, the signal light 711 that is diffused by the light diffuser 2 and reaches the linear Fresnel lens 4 is indicated by eight arrows. The linear Fresnel lens 4 collimates the signal light diffused by the light diffuser 2 and incident on the linear Fresnel lens 4. Specifically, the linear Fresnel lens 4 does not collimate the signal light incident on the linear Fresnel lens 4 in the thickness direction of the light transmission layer 1 but has a focus on the light diffuser 2. And collimate in the width direction of the light transmission layer 1. Therefore, of the signal light 711 collimated by the linear Fresnel lens 4, most of the signal light collimated at the portion of the linear Fresnel lens 4 facing each light-collecting sheet 5 enters each light-collecting sheet 5. . As shown in FIG. 4, the signal light incident on each light-collecting sheet 5 is collected while being totally reflected on the front and back surfaces of each light-collecting sheet 5 or directly toward each light-receiving element 71, and is collected by each light-receiving element 71. Received. FIG.
2, the signal light 711 received by the light receiving element 71 from the inside of the light transmission layer 1 through the inside of the light-collecting sheet 5 is indicated by a large number of lines.

In this embodiment, the case where the signal light is emitted from the circuit board 6 disposed at the innermost position among the four circuit boards 6 shown in FIG. 1 has been described. Also when the signal light is emitted from the substrate 6,
Again, the signal light has its optical path converted by the linear Fresnel lens 3 toward the light diffuser 2, is diffused by the light diffuser 2 toward the linear Fresnel lens 4, and the diffused signal light is converted by the linear Fresnel lens. 4, the light is collimated only in the width direction and emitted from the linear Fresnel lens 4.
Most of the signal light emitted from the portion facing the light incident on each light condensing sheet 5 and received by each light receiving element 71.

An experimental result of examining the light-collecting efficiency of the light-collecting sheet 5 provided in the signal processing device 100 will be described below.

In conducting this experiment, one optical bus 20, one light-collecting sheet 5, and one light-receiving element 71 were prepared. These prepared optical buses 20 have a side length of 60.
mm, the thickness is 1 mm, and the width of the condensing sheet 5 is 8 mm.
And the light receiving diameter of the light receiving element 71 is 5 mmφ.

A light receiving element 71 is arranged on the end face 5 b of the light-collecting sheet 5 prepared above, and the cylindrical lens surface 5 a of the light-collecting sheet 5 is opposed to the linear Fresnel lens 4 of the optical bus 20. 5 was moved in the longitudinal direction of the linear Fresnel lens 4 together with the light receiving element 71, and the light intensity received by the light receiving element 71 when the signal light was incident on the linear Fresnel lens 3 was determined. Further, only the light receiving element 71 was opposed to the linear Fresnel lens 4 of the optical bus 20, the light receiving element 71 was moved in the longitudinal direction of the linear Fresnel lens 4, and the light intensity received by the light receiving element 71 was also determined.

FIG. 5 shows the results of the experiment.

The horizontal axis of the graph is the linear Fresnel lens 4
Is the arrangement position of the light-collecting sheet 5 (the light-receiving element 71 when only the light-receiving element 71 is opposed) with respect to the longitudinal direction, and the vertical axis is the intensity of light received by the light-receiving element. The position of the light-condensing sheet 5 (the light-receiving element 71 when only the light-receiving element 71 is opposed to the light-receiving element 71) when the light-condensing sheet 5 is opposed to the central portion of the linear Fresnel lens 4 is set.
The arrangement position of 1) is defined as a reference position (0 mm), and is represented by a distance from the reference position.

FIG. 5 shows that the provision of the light-collecting sheet allows light to be efficiently received.

The operation of the signal processing device 100 will be described below in comparison with two signal processing devices A and B having different configurations from the signal processing device 100.

FIG. 6 shows a signal processing device A of one of two signal processing devices A and B having a configuration different from that of the signal processing device 100 according to the second embodiment of the present invention. FIG. 3 is a top view showing the circuit board side where the circuit board is placed.

A signal processing device 10 according to a second embodiment of the present invention
6 (see FIG. 1) and the signal processing device A shown in FIG. 6 is that the signal processing device 100 has a light-collecting sheet 5 that spreads in the same direction as the light transmission layer 1 on the front surface of the light receiving element 71. The signal processing device A shown in FIG. 6 has a light receiving element 171 instead of the circuit board 7.
Is provided with a circuit board 170 on which a biconvex lens 150 having both convex surfaces is mounted.

In the signal processing device A shown in FIG. 6, the signal light 1711 diffused by the light diffuser 2 and collimated by the linear Fresnel lens 4 (this signal light 1711 is shown by eight arrows in FIG. 6). ), The ratio of the signal light 1712 propagating in the direction deviating from the arrangement position of the biconvex lens 150 is large, and the light use efficiency is low.
At 0, as shown in FIG. 3, since each condensing sheet 5 spreads in the same direction as the light transmission layer 1, the arrangement of the condensing sheet 5 in the signal light 711 collimated by the linear Fresnel lens 4 is The ratio of the signal light propagating in the direction shifted from the position can be reduced, and the light use efficiency can be increased.

FIG. 7 is a top view showing a circuit board side on which a light receiving element is mounted, of another signal processing device B having a configuration different from that of the signal processing device 100, and FIG. 8 is a side view thereof.

The difference between the signal processing device 100 and the signal processing device B shown in FIG. 7 is that the signal processing device 100 includes a condensing sheet 5 that spreads in the same direction as the light transmission layer 1 on the front surface of the light receiving element 71. While having the mounted circuit board 7,
A signal processing device B shown in FIG. 7 includes a circuit board 170 on which a light receiving element 171 is mounted instead of the circuit board 7, and a biconvex lens 15 shown in FIG.
The only difference is that a biconvex lens 151 having a diameter larger than 0 is provided.

The signal processing apparatus B shown in FIG. 7 has a biconvex lens 15 having a larger diameter than the biconvex lens 150 shown in FIG.
1, the signal light 1711 collimated by the linear Fresnel lens 4 more than the signal processing device A shown in FIG. 6 (this signal light 1711 is indicated by four arrows in FIG. 7). Can be efficiently converged toward the light receiving element 171. However, most of the signal light 1711 arriving at the linear Fresnel lens 4 reaches the linear Fresnel lens 4 by repeatedly and totally reflecting the front and back surfaces of the optical transmission layer 1 as shown in FIG. Is a signal light 1 that repeatedly and totally reflects the front and back surfaces of the optical transmission layer 1.
711 are indicated by multiple lines). Therefore, the signal light 1711 arriving at the linear Fresnel lens 4 is collimated by the linear Fresnel lens 4 to form the biconvex lens 1
8, the signal light propagates toward the light receiving element 171 while spreading in the thickness direction of the optical transmission layer 1 as shown in FIG. The ratio of light received at 171 is low.

On the other hand, in the signal processing device 100, as shown in FIG. 3, a sheet-shaped condensing sheet 5 that spreads in the same direction as the light transmission layer 1 is provided at a position facing the linear Fresnel lens 4. . Therefore, the linear Fresnel lens 4
From the cylindrical lens surface 5 of the condensing sheet 5
As shown in FIG. 4, most of the signal light incident on the light receiving element a is collected toward the light receiving element 71 while being totally reflected on the front and back surfaces of the light collecting sheet 5. You. Therefore, the signal light incident on the light-collecting sheet 5 is efficiently received by the light receiving element 71.

Next, a signal processing apparatus according to a third embodiment of the present invention will be described. In describing the signal processing device according to the third embodiment, the signal processing device according to the second embodiment of the present invention described above (for example, see FIG. 1)
Only the differences from the above will be described.

The difference between the signal processing devices of the second and third embodiments is that the signal processing device of the third embodiment is different from the signal processing device of the second embodiment in that the light-collecting sheet 5 (for example, see FIG. 3). The only difference is that a light-collecting sheet having a configuration different from that of the light-collecting sheet is provided.

FIG. 9 is a plan view showing a condensing sheet provided in the signal processing device of the third embodiment. This figure 9
FIG. 3 also shows, in addition to the light-collecting sheet 60, a portion of the linear Fresnel lens 4 provided in the signal processing device of the third embodiment, which faces the light-collecting sheet 60.

The hologram 60a is formed at the end of the light-collecting sheet 60 facing the linear Fresnel lens 4. The end face 60b of the light collecting sheet 60 on the side where the hologram 60a is formed is formed flat so as to be along the linear Fresnel lens 4. Also, hologram 6
0a has a focus on the end face 60c of the light-collecting sheet 60 opposite to the end face 60b facing the linear Fresnel lens 4.

The difference in the operation of the light-collecting sheets 5 and 60 provided in the signal processing devices of the second and third embodiments will be described below with reference to FIG.

FIG. 10 is a plan view (a) showing the light-condensing sheets 5 and 60 provided in the signal processing devices of the second and third embodiments, respectively.
A ′ sectional view (b), BB ′ of those light-collecting sheets 5 and 60
It is sectional drawing (c). 10 (a) to 10 (c).
, The condensing sheets 5 and 60 of the linear Fresnel lens 4
Are also shown.

As shown in FIG. 10A, the condensing sheet 5 provided in the signal processing device of the second embodiment has an end face facing the linear Fresnel lens 4 formed on a cylindrical lens face 5a. Therefore, as shown in FIG. 10B, most of the signal light 41 emitted from the portion of the linear Fresnel lens 4 that passes through the broken line AA ′ enters the light-collecting sheet 5. However, the cylindrical lens surface 5
Since a has a curvature, the distance between the linear Fresnel lens 4 and the cylindrical lens surface 5a is as shown in FIG.
As shown in FIG. 7, the width increases from the broken line AA ′ to the broken line BB ′. Therefore, as shown in FIG. 10C, the signal light 42 emitted from the portion of the linear Fresnel lens 4 that passes through the broken line BB ′ passes through the signal light that is emitted from the portion that passes through the broken line AA ′. Compared to the light, in the thickness direction of the light-collecting sheet 5, the amount of signal light traveling in the direction shifted from the cylindrical lens surface 5a increases, and the use efficiency of the signal light decreases.

On the other hand, the end face 60b of the condensing sheet 60 provided in the signal processing device of the third embodiment is the same as that shown in FIG.
As shown in FIG. 3A, it is formed flat along the linear Fresnel lens 4. Therefore, even if the signal light emitted from the linear Fresnel lens 4 is emitted from a different position in the longitudinal direction of the linear Fresnel lens 4, as shown in FIG. 10B and FIG. Most of the signal lights 43 and 44 emitted from the lens 4 enter the light-collecting sheet 60. That is, the light-collecting sheet 6
By using 0, the signal light emitted from the linear Fresnel lens 4 can be more efficiently condensed toward the light receiving element than the condensing sheet 5 provided in the signal processing device of the second embodiment. .

In the signal processing device according to the third embodiment, the light-collecting sheet 60 having the hologram 5a is used as a light-collecting sheet having a flat end surface facing the linear Fresnel lens 4.
However, instead of the light-collecting sheet 60, for example, a light-collecting sheet having a refractive index distribution or a light-collecting sheet having a grating diffraction lens may be used.

FIG. 11 is a perspective view showing a signal processing apparatus according to a fifth embodiment of the present invention provided in the second optical transmission system according to the fourth embodiment of the present invention, and FIG.
FIG. 2 is a view of the signal processing device shown in FIG. In FIG. 12, an optical bus 3 included in the optical transmission system is provided.
Reference numeral 0 denotes a cross-sectional view including the light diffuser 2 as viewed from the AA direction.

As shown in FIG. 11, the signal processing device 400 includes a motherboard 10 (an example of a base according to the present invention).
The optical bus 30 is fixed to the motherboard 10. This optical bus 30 is an optical bus 20 included in the optical transmission system 50 according to the first embodiment of the present invention.
Six optical transmission layers 1 having the same structure as that of FIG. 1 and having a light diffuser 2 at the center and linear Fresnel lenses 3 and 4 adhered to both end surfaces are provided (see FIG. 12). The plurality of light transmission layers 1 are alternately stacked with a cladding layer 250 having a lower refractive index than that of the light transmission layer 1 interposed therebetween.

As shown in FIG. 11, the signal processing device 400 includes four circuit boards 41 on one side of the optical bus 30.
0 and four circuit boards 420 on the opposite side. The circuit board 410 of the circuit boards 410 and 420 has six light emitting elements 411 mounted thereon corresponding to the six light transmission layers 1 provided in the optical bus 30.
Each of the two light emitting elements 411 is a linear Fresnel lens 3 of each of the six light transmission layers 1 provided in the optical bus 30.
Is an element that emits signal light. In addition, the circuit board 4
An electronic circuit 412 is mounted on 10. The electronic circuit 412 is a circuit that generates a signal to be carried by the signal lights emitted from the six light emitting elements 411. On the other hand, on the circuit board 420 disposed on the opposite side of the optical bus 30, six light-collecting sheets 421 and six light-receiving elements 422 are mounted corresponding to the six light transmission layers 1 provided in the optical bus 30. Have been. These six light-collecting sheets 421 are for condensing the signal light emitted from the linear Fresnel lenses 4 of each of the six light transmission layers 1 toward the light-receiving element 422, and the light-collecting sheet 5 (see, for example, FIG. 1). ) Is a sheet having the same structure as in FIG. The light receiving element 422 is an element that receives the signal light collected by the light collecting sheet 421. Further, an electronic circuit 423 is mounted on the circuit board 420. The electronic circuit 423 is a circuit that performs signal processing based on a signal carried by the signal light received by the light receiving element 422.
In FIG. 12, the electronic circuits 412 and 423 mounted on the circuit boards 410 and 420 are not shown.

As shown in FIG. 11, fixed portions 430 and 440 for detachably fixing the circuit boards 410 and 420 are provided on the motherboard 10, and when the circuit board 410 is mounted on the fixed portion 430, Each of the six light emitting elements 411 mounted on the circuit board 410 is connected to the optical bus 30.
The motherboard 1 is placed in an optically coupled state with the linear Fresnel lens 3 of each of the six light transmission layers 1 provided by the
0 on the other hand, while the circuit board 420
Is mounted, each of the six light-collecting elements 422 mounted on the circuit board 420
The optical transmission layer 1 is fixed on the motherboard 10 so as to be optically coupled to the linear Fresnel lens 4 of each layer. The combination of the optical bus 30 and the light-collecting sheet 421 mounted on each circuit board 420 corresponds to the second optical transmission system according to the present invention.

The signal processing device 400 thus configured
When the electronic circuit 412 mounted on the circuit board 410 generates a signal to be carried by the signal light emitted from the light emitting element 411, the signal light carrying the signal is emitted from the light emitting element 411. The signal light enters the linear Fresnel lens 3 of the optical bus 30, and the optical path is converted toward the light diffuser 2 provided in the optical transmission layer 1. The signal light whose optical path has been converted is diffused by the light diffuser 2 and collimated by the linear Fresnel lens 4 only in the width direction of the light transmission layer 1. The collimated signal light is condensed by the light condensing sheet 421 toward the light receiving element 422, and the condensed signal light is received by the light receiving element 422,
At 23, signal processing is performed.

Since the signal processing device 400 includes the optical bus 30 and the condensing sheet 421 having the above configuration, the signal light emitted from the light emitting element 411 can be efficiently received by the light receiving element 422. it can.

Further, the signal processing device 400 is capable of transmitting the signal light emitted from the linear Fresnel lens 4 of each of the six optical transmission layers 1 provided in the optical bus 30 to each of the condensing sheets which spread two-dimensionally. The light condensing sheet 421 condenses light toward the light receiving element 422 at each light transmission layer 1.
It is arranged so as to spread in the same direction as. If the biconvex lens 151 shown in FIGS. 7 and 8 is used instead of the light-collecting sheet 421, it is necessary to increase the diameter of the biconvex lens 151 in order to improve the light receiving efficiency of the light receiving element 422. There is. Therefore, in order to dispose the biconvex lens 151 corresponding to each linear Fresnel lens 4 of each optical transmission layer 1, it is necessary to increase the thickness of the optical transmission layer 1 itself, and the optical bus 30 itself becomes large. There is a problem,
As shown in FIG. 11, in the signal processing device 400, each light condensing sheet 421 is arranged so as to spread in the same direction as each light transmission layer 1. Therefore, it is unnecessary to increase the thickness of the optical transmission layer 1 itself, and the size of the signal processing device 400 can be reduced.

[0052]

According to the present invention, an optical transmission system capable of efficiently condensing signal light on a signal light receiving element and having a reduced size even in a structure corresponding to multi-bits, and an optical transmission system therefor. A signal processing device employing the optical transmission system is obtained.

[Brief description of the drawings]

FIG. 1 is a top view illustrating a signal processing device according to a second embodiment of the present invention, including an optical transmission system according to the first embodiment of the present invention.

FIG. 2 is a diagram of the signal processing device shown in FIG. 1 as viewed from a direction AA.

FIG. 3 is a diagram showing a right half (on the side of the linear Fresnel lens 4) of the optical bus shown in FIGS. 1 and 2, and a circuit board 7 arranged to face the linear Fresnel lens 4;

FIG. 4 is an enlarged side view of a portion where a linear Fresnel lens, a light collecting sheet, and a light receiving element are arranged.

FIG. 5 is a diagram showing experimental results.

6 is a top view showing one of two signal processing devices A having a configuration different from that of the signal processing device 100, on a circuit board side on which a light receiving element is mounted; FIG.

7 is a top view of another signal processing device B having a configuration different from that of the signal processing device 100, showing a circuit board side on which a light receiving element is mounted. FIG.

FIG. 8 is a side view of FIG. 7;

FIG. 9 is a plan view illustrating a light-collecting sheet included in a signal processing device according to a third embodiment.

FIG. 10A is a plan view in which light collecting sheets 5 and 60 included in the signal processing devices of the second and third embodiments are arranged, and FIG. (B), BB 'sectional drawing (c) of those light collection sheets 5 and 60.

FIG. 11 is a perspective view illustrating a signal processing device according to a fifth embodiment of the present invention provided in an optical transmission system according to a fourth embodiment of the present invention.

12 is a diagram of the signal processing device shown in FIG. 11 as viewed in the direction of arrows AA.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical transmission layer 2 Light diffuser 3, 4 Linear Fresnel lens 5, 60, 421 Condensing sheet 5 a Cylindrical lens surface 5 b, 60 b, 60 c End surface 6, 7, 170, 410, 420 Circuit board 10 Motherboard 20, 30 Optical bus Reference Signs List 50 optical transmission system 60a hologram 61,411 light emitting element 71,171,422 light receiving element 100,400 signal processing device 150,151 biconvex lens 250 clad layer 412,423 electronic circuit 430,440 fixing part 611,711,1711,1712 , 1713 signal light

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shinya Kyozuka 430 Sakai Nakaicho, Ashigara-gun, Kanagawa Green Tech Nakai Fuji Xerox Co., Ltd. F-term (reference) 2H037 AA01 BA03 BA11 BA23 CA17 CA33

Claims (5)

[Claims] 1. A signal light having a shape that spreads two-dimensionally, enters signal light from one edge, propagates the incident signal light toward the other edge, and transmits the signal light from the other edge. An optical bus main body having a light diffusing means for diffusing signal light at a predetermined point in the optical bus main body, and an incident signal light provided on the one edge side. An optical path changing means for directing the light to the light diffusing means arranged at the predetermined point;
An optical bus provided on the other end side, and a collimating means for collimating the signal light diffused by the light diffusing means and emitted from the other end, and on the other end side of the optical bus main body. An optical transmission system, comprising: a light-collecting element provided to have a shape extending in the same direction as the optical bus main body and to collect a part of the signal light collimated by the collimating means. 2. An end of the light-collecting element on the side of the optical bus main body, which is a cylindrical lens surface having a focal point on an end opposite to the side of the optical bus main body. The optical transmission system according to the above. 3. The hologram lens according to claim 1, wherein an edge of the light-collecting element on the side of the optical bus main body is a hologram lens surface having a focal point on an edge opposite to the side of the optical bus main body.
The optical transmission system according to the above. 4. It has a shape that spreads two-dimensionally, receives signal light from one edge, propagates the incident signal light toward the other edge, and transmits the signal light from the other edge. A plurality of light transmission layers having light diffusion means for diffusing signal light at each predetermined point in each light transmission layer,
An optical bus main body in which one edge of each of the plurality of optical transmission layers faces in the same direction and the other edge faces in the same direction and is sequentially stacked; and Optical path conversion means provided on one end side of the optical bus for directing incident signal light to each light diffusion means arranged at a predetermined point of each of the plurality of optical transmission layers; and the other end side of the optical bus main body. Provided on the optical bus, and a collimating means for collimating the signal light emitted from the other end of the optical bus main body diffused by the respective light diffusing means, and on the other end side of the optical bus main body. Provided in correspondence with each of the plurality of light transmission layers, has a shape extending in the same direction as the light transmission layers, and emits a part of the signal light emitted from the corresponding light transmission layers and collimated by the collimating means. Condensing, Optical transmission system characterized by comprising a plurality of condensing elements arranged in the stacking direction of the climate transmission layer. 5. A plurality of first circuit boards on which a base, a signal light emitting body for emitting signal light, and a circuit for generating a signal to be carried by the signal light emitted by the signal light emitting body are mounted. And a light-collecting element that has a shape that spreads two-dimensionally and that condenses a part of the signal light collimated by the collimating means onto the signal-light incident body. A plurality of second circuit boards mounted with a circuit for performing signal processing based on a signal carried by the incident signal light, having a two-dimensionally spread shape, receiving the signal light from one edge, An optical bus main body for propagating the signal light toward the other end and emitting the signal light from the other end, and diffusing the signal light to a predetermined point in the optical bus main body. An optical bus main body having a means, and an incident light provided on the one edge side. An optical path changing means for directing the signal light to a light diffusing means disposed at the predetermined point; and a collimating signal light provided on the other edge side and diffused by the light diffusing means and emitted from the other edge. An optical bus provided with a collimating means, and a plurality of first circuit boards, each of which is provided with a signal light emitting body mounted on each of the plurality of first circuit boards. The plurality of second circuit boards are fixed to the base in an optically coupled state, and the plurality of light collecting elements mounted on each of the second circuit boards are in the same direction as the direction in which the optical bus extends. A signal processing device, comprising: a plurality of base fixing portions that are fixed on the base in a state of spreading in the direction and being optically coupled to the other end of the optical bus.